Just a perimeter fence, I have over the years occasionally lost a chicken to Raptors, but the size of my run precludes an overhead net. However there are so many trees and bushes in the run, there are lots of places to hide. Also I now have Guineas incorporated into the flock and they spot danger long before the chickens do and warn.
How do u keep them from flying out? Was it hard to mix the guineas in the flock?